The invention relates to a single wheel suspension of a non-steerable wheel of a two track vehicle.
The rear axles of passenger vehicles with wheels that cannot be typically steered, have, as is well-known, a decisive impact on the driving stability and safety of the vehicle. In order to attain a stable handling of the vehicle in virtually all driving situations, modern rear axles are designed with such kinematic properties that they generate a negative camber angle on the wheel by way of the spring compression travel in order to maximize the transferable lateral forces relative to the vehicle body. In addition, a toe-in angle at the wheel is desired in terms of the kinematic effects over the spring compression travel of the wheel relative to the vehicle body and in terms of the elastokinematic effects under the longitudinal forces acting on the wheel (in particular, by decelerating), in order to generate an understeering handling of the vehicle and to prevent the rear from suddenly breaking away when there is a change in the wheel load. Such a behavior that matches the above general description is distinguished by relatively costly axle designs, for example in the form of five link axles or semi-trailing arm axles. However, these axle designs have not only the drawback of high costs, but they also have additionally a high installation space requirement. In contrast, the so-called torsion beam rear axles, which are known to the person skilled in the art, are more advantageous, but they also exhibit certain drawbacks with respect to the driving dynamics of motor vehicles.
Working on this basis, there is a need for a single wheel suspension that is advantageous or attractive with respect to the driving dynamics of the motor vehicle and that is distinguished by a small installation space requirement and a simple design.
The solution of this problem lies in a single wheel suspension of a non-steerable wheel of a two track vehicle (also known as a double or dual track vehicle) having two links, which can be pivoted relative to each other in a plane, wherein each of the planes is inclined by not more than 10° (or more specifically by not more than an angle in an order of magnitude from 6° to) 10° relative to the longitudinal direction of the vehicle and by not more than 10° (or more specifically by not more than an angle in an order of magnitude from 6° to 10°) relative to the vertical. Furthermore, the following features are present. The first link, which extends approximately in the longitudinal direction of the vehicle, also assumes the function of a wheel carrier (known to the skilled person in the art), in that a wheel bearing is fastened in an end section of the link in a receptacle; and the vehicle wheel is mounted in a rotational manner on the first link by way of the wheel bearing. Furthermore, the first link is supported with its other end section on the vehicle body by way of a pendulum support, which extends essentially in the vertical direction in the as-designed position. The other, second link, which extends essentially in the longitudinal direction of the vehicle, is supported on the one side in an articulated manner on the vehicle body with only one kinematic rotational degree of freedom and on the other side is connected in an articulated manner to the first link between the wheel bearing and the fastening point of the pendulum support with only one kinematic rotational degree of freedom. The wheel is guided relative to the vehicle body only by way of these two links. That is, no other wheel guiding link is provided, save for a connecting element, which may be provided, if desired, between the first link and the second link (in order to represent the articulated connection between these two link).
The above-described features provide an extremely compact single wheel suspension that requires very little installation space especially when viewed in the transverse direction of the vehicle. As a result, the single wheel suspension makes available a large amount of useable free space between the two wheels of a vehicle axle, in particular the rear axle due to the non-steerable wheels. Of course, it is also possible to permit slight elastokinematic steering movements of the wheel. Furthermore, a compression and decompression movement of the wheel in the vertical direction relative to the vehicle body may affect small desired changes in the track (toe-in), and in particular, owing to the slight inclination in the planes, in which each of the two links can be kinematically pivoted. In this respect these planes are inclined, as stated, relative to the vertical and/or relative to the longitudinal direction of the vehicle. Hence, a desired toe-in change and/or camber change when the wheel is running and/or when external forces are being applied and thus, the desired driving stability of a single wheel suspension, can be produced with a pivoting movement of the links in these planes.
The above concept “kinematically pivotable” is used to explicitly exclude the elastokinematic effects known to the person skilled in the art. Since each of the two links can be kinematically pivoted exclusively in one plane, each link has only one single kinematic rotational degree of freedom. In addition to this kinematic rotational degree of freedom it is also possible for the movements of the (respective) link to deviate slightly, subject to the corresponding action of the forces, from the (respective) degree of freedom even when suitable rubber bearings are provided. However, just slightly differing movements can take place only in a rubber bearing, assigned to the link, without the influence of correspondingly large forces and without elastic deformations.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.